 In this demo, we're showing the capability of the ST Time of Flight sensor to count the number of people entering and exiting a room. To do this, we've set up a quick mock-up of the evaluation kit on the left and we've connected an external sensor. You can see it mounted to the door jam. We've used the standard STM32 and we've connected it to a rather large battery that doesn't need to be anywhere near that big. The heart of the matter is this tiny little sensor at J2. The time of flight sensor shoots out a flash of light and receives the photons that bounce off the target, giving you a distance. The way it works is that the field of view is divided up into two zones, an inner and an outer. As the person walks into the room, he is seen in the outer zone. He is then detected in the inner zone. As he fully enters the room, we increment the count by one. In this video, we show a typical meeting starting with passerbys not affecting the count and collisions, partial entries don't seem to hurt it, chairs are not a problem, and door closings don't add to the count either. Passerby again with the door closed and when your meeting is canceled, partial entries don't affect it. When everyone leaves, we end with a proper count.